Can someone please explain to me, how to make a dovetail, slide-in kerf insert for my MFT? Better yet, maybe there's a vid on it, but I haven't been able to find one? I know lots of folks consider their tops to be disposable, however I don't. Thanks for the help.
Dovetail Kerf Insert For MFT
- Thread starter darita
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NiteWalkerGR
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IMHO, I'd just use a piece of straight 1/4" MDF and stick it in place with double sided tape. Make sure to seal the routed slot in the MFT. I like dewaxed shellac. Quick, simple, fast drying, plenty durable.
Making the dovetail slot is easy enough, but it needs to be more precise than a simple channel for a straight piece, and it's still possible for it to bow and lift in the center, hence why I prefer the double sided tape approach.
You just rout it like you would any slot, but use the dovetail bit instead of a straight. On the insert pieces you just cut a matching angle on the edges (commonly 7 or 14 degrees) and sneak up on the fit.
Making the dovetail slot is easy enough, but it needs to be more precise than a simple channel for a straight piece, and it's still possible for it to bow and lift in the center, hence why I prefer the double sided tape approach.
You just rout it like you would any slot, but use the dovetail bit instead of a straight. On the insert pieces you just cut a matching angle on the edges (commonly 7 or 14 degrees) and sneak up on the fit.
Michael Kellough
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[member=25351]rst[/member] How thick is the UHMW PE stock? And how did you cut it?
Making the first bevel on the plastic stock with the router is easy to imagine but how did you cut the second bevel? Specifically, how did you secure the narrow flexible plastic strip? Or did you plow through with the dovetail bit in one pass?
I’m guessing you’d flip the stock over and make the second cut with the track saw set to a 7* bevel?
Making the first bevel on the plastic stock with the router is easy to imagine but how did you cut the second bevel? Specifically, how did you secure the narrow flexible plastic strip? Or did you plow through with the dovetail bit in one pass?
I’m guessing you’d flip the stock over and make the second cut with the track saw set to a 7* bevel?
Cheese
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I made a slide-in dovetail kerf strip 25+ years ago for some motorcycle chain rub guides. Put the material in the milling machine vise, dovetailed each side and cut off the extra material on the bottom of the strip. Then I machined the steel mounts to fit the kerf strip into.
A lot of work and I'm not convinced it's worth the effort. Bottom line is, the insert material likes to move around when machining it and you really need to machine the slot to fit the insert otherwise you'll be chasing your tail. [smile]
If I were doing this (and I have been thinking seriously about it) I would probably do what NiteWalker suggested and use straight strips that can be ripped on a table saw or band saw and then double-stick-tape them into the slot.
If you decide to pursue the dovetail method, I'd strongly suggest you manufacture several replacement strips at the same time for future use. In 3-4 years when you want to replace the insert, you'll thank your lucky stars you did that.
A lot of work and I'm not convinced it's worth the effort. Bottom line is, the insert material likes to move around when machining it and you really need to machine the slot to fit the insert otherwise you'll be chasing your tail. [smile]
If I were doing this (and I have been thinking seriously about it) I would probably do what NiteWalker suggested and use straight strips that can be ripped on a table saw or band saw and then double-stick-tape them into the slot.
If you decide to pursue the dovetail method, I'd strongly suggest you manufacture several replacement strips at the same time for future use. In 3-4 years when you want to replace the insert, you'll thank your lucky stars you did that.
Michael Kellough
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I like the idea of a replacement strip but in practice I keep it simple. I just fill an excessively wide slot with wood filled epoxy putty, scrape level, then do as little sanding as required.
But I try to preserve the kerf by using a sacrificial surface on top of the MFT when cutting a bevel. Never using the Panther blade on the MFT helps a lot.
I also use the sacrificial panel when cutting thin stuff to keep the guide rail close to the elevation where it was last calibrated. The more you change elevation on the stock MFT rail brackets the more likely you’ll loose square. Since darita is using the Dashboard brackets…
But I try to preserve the kerf by using a sacrificial surface on top of the MFT when cutting a bevel. Never using the Panther blade on the MFT helps a lot.
I also use the sacrificial panel when cutting thin stuff to keep the guide rail close to the elevation where it was last calibrated. The more you change elevation on the stock MFT rail brackets the more likely you’ll loose square. Since darita is using the Dashboard brackets…
mgrobins
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Why make this complex joinery?
1. Choose a sacrificial material so you know the dimension for depth.
2. Cut the sacrificial material to desired width
3. Cut groove on MFT to fit it - and your fixing material (eg double sided tape), so that your work surface is still at correct level.
4. Fit the insert.
5. Work hard to pay off your tools.
1. Choose a sacrificial material so you know the dimension for depth.
2. Cut the sacrificial material to desired width
3. Cut groove on MFT to fit it - and your fixing material (eg double sided tape), so that your work surface is still at correct level.
4. Fit the insert.
5. Work hard to pay off your tools.
derekcohen
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- Jun 22, 2008
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- 930
darita said:
Like this?
I did this with hand tools.
Create the socket ...
Level the floor ...
The sides were chiseled to shape using two of the inserts made (with a dovetail plane) ...
... and slid in.
Regards from Perth
Derek
Birdhunter
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That looks far more elegant than the two part epoxy wood filler I used.
derekcohen
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rst said:
I have made many fixtures or parts from UHMW, even a drill press table …
As has been mentioned, it is overdone -expensive - for a MFT insert. Plus you will not like having to shape it. UHMW is a struggle to saw, as the shavings clog up everything. Be prepared to pull all apart afterwards to clear the machines.
Regards from Perth
Derek
